[erangi]

Our app uses DCOM to connect to our propriety server. I'm now setting up my first Windows 7 workstation, and have encountered a problem connecting to a dev server running on an XP machine. Here are the details:

1. Connection (CoCreateInstanceEx) returns a "The RPC server is unavailable" error.
2. Event Viewer has a message saying "DCOM was unable to communicate with the computer n.n.n.n using any of the configured protocols".
3. I'm logged into both machines with the same (domain) user.
4. From both machines I can access the other machine's C$.
5. No firewall in either machine.
6. The app is run as an administrator.
7. On the 7 machine, the app can connect to a server running on a Win2003 machine with no problem, meaning there's no problem with the app's installation.
8. An app running on a different XP machine can connect to the XP server with no problem, meaning there's no problem with the server's installation.
9. The call never seems to get to the server, as the server service is not being automatically started once a call is done from the 7 machine.

I've had my share of DCOM connection problems over the years, but this one beats me. Any ideas what might be the problem?